Expansible pulley.



M. L. SEVERY. EXPANSIBLB PULLBY,

APPLIGATION FILED JULY s, 191s 1,132,125. Patented Mar.16,1915.

THE Nvnms n; I'ERS Cn.. PHOTG-LITHO.. WASHINGTON, D. C.

M. L. SEVERY.

BXPANSIBLE PULLBY,

APPLICATION FILED JULY a, 191s.

1,132,125., Patented Mar.16,1915.

2 SHEETS-SHEET 2.

a este.

MELVIN L. SEVERY, 0F ARLINGTON HEIGHTS, MASSACHUSETTS, ASSIGNOR TO SEVERY MANUFACTURING COMPANY, 0F BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

EXPANSIBLE PULLEY.

Fatented Mar. 16, 1915.

Application filed July 8, 1913. Serial No. 777,872.

To alt whom t may concern:

Be it known that I, MiiLviN L. SEvnnY, of Arlington Heights, in the county of MiddleseX and State of Massachusetts, have invented certain new and useful Improvements in Expansible Pulleys, of which the following is a specification.

This invention relates to an improvement in expansible pulleys. p l n The object of the invention is to provide an expansible pulley which is composed of parts that can be readily produced by die casting and are readily assembled, and which can be used in coacting pairs controlled by a single movement.

The invention will be clearly understood from an inspection of the accompanying drawings, in which- Figure 1 is a plan view showing a pair of pulleys arranged for coaction, together with the means for controlling them, Fig. 2 is a face view of one of the pulleys, showing the upper half of the inner plate removed, F ig. 3 is a fragmentary central vertical section through one end of a pulley, Fig. t is a plan view of the pulley partly expanded, Fig. 5 is a face view, on an enlarged scale, of one of the ball-carriers, Fig. 6 is a section taken on the line 6-6 in Fig. 5, Fig. 7 is a section taken on the line 7-7 in Fig. 5, Fig. 8 is a section taken on the line 8-8 in Fig. L1, Fig. 9 is a sectional detail view of a portion of the upper end of two adjacent ball-carriers.

As illustrated in the drawings, the preferred embodiment of the pulley comprises a pair of anges, each composed of an inner plate 10, having an outer liat face provided with radial slits 12 through which projections 14: extend, said projections being formed on bars 16, which extend between said flanges and form the movable vanes or sections of the pulley. Each vane comprises a dentated peripheral member 18, which may be formed integral with the bar 16, or aixed thereto by screws 20. lllhe dentations of the vanes intermesh in such a manner that when said vanes are in their innermost position they form a substantially continuous peripheral surface, and when they are in their outermost position the edges of the teeth are practically in line or separated'slightly, so that there is little or no continuous break in the periphery of the pulley. Thus the periphery of the pulley is formed with small apertures and a good traction surface is provided over which a slitted belt may be most advantageously used, as this belt is exceedingly flexible and therefore readily conforms to the surface of the pulley, and for the further reason that this form of pulley does not require a belt to engage it so as to form a suction with its periphery.

The projections 14 are formed with reduced ends 22, which project into grooves 24: formed in plates or ball-carriers 26. These plates are triangular, as shown in Fig. 5, said plates being preferably attached to the rear faces of the plates 10. rThe rear faces of the plates 10 are irregular to lit the plates 26, the latter being located diagonally and having the grooves 24 extend in a triangular path to form race-ways for endless series of balls 28, the projections 22 being adapted to enter between two of the balls and be engaged thereby to vary the positions of the varies 18, when the diameter of the pulley is changed. The plates 26 may be held in place upon the plates 10 by means of screws 30, which pass through the plates 26 into the plates 10, and when said plates 26 are in place their ball-races are closed except where they communicate with the radial slots 12 and the peripheral slots 36.

Surrounding the plates 10 and 26 is a cover-plate 32, having a series of inwardly projecting teeth 34, said teeth being inclined like the plates 26 and adapted to enter the ball-races 24 through slots 36 formed in the tops of the plates 26. The cover plate 32 may be made in sections with integral teeth to facilitate the work of assembling. The teeth 34 pass between two balls 28 and operate to push the same around the race-ways when the cover-plate 32 is given a rotary motion. A coiled spring 2O may be interposed in the ball circuit to take up slack and prevent rattling. Where the ball runways communicate with the slots 12 and 36 the former are made shallower than throughout the remainder by the amount which these openings allow the ball surface to protrude. lThis is shown in Fig. 7 and is to prevent the balls from staggering at these points and thus crowding one another instead of having a continuous line of contact through their centers. Each of the triangular plates 26 is formed with a ledge 27 at its upper rear edge (see Fim 9), which projects into the recess formed in the next 11G plate, said ledge forming one wall of the peripheral slot 36 in which the toothv34 travels. p Y

The cover plate 32 is formed with one end 5 wallV 38 having a boss 40 within whicha sleeve 42 is adapted to slide, said boss and wall being provided interiorlv with a pair of circular channels having endless series ofballs 44, said balls being arranged to engage a diagonally extending spline 46 on said sleeve. the` width of the pulley and is provided at its other end with a diagonally extending spline 46, which engages a grooved boss 5() on a cover-plate52' fo'rming'the correspond'-v ing end of the pulley.

The pulleys; are adapted to be used in co4 acting pairs, as shown in Fig. l, in which the pulleys 60', 6l are mounted' on" shafts 2d 62, 64 jou'rnaled in suitable bearings 66, 67.

Upon the shafts 62, 64 are slidably mounted the sleeves- 42, 42a, having grooved collars 618, 68a, and held against relative' rotation with their shafts by splines 70. A lever 72 251is fulcrumed at 74 and provided with a han-y dle 76 for operation. The lever 72 is Vprovided-with' means at its ends for engaging the grooved collars 68, 68a, so that the 'sleeves'-y 42 and' 42'nl may be `moved longitudinally 3'wi`th'respect to their shafts to adjust the diameters of the pulleys 60, 61. This lever is'alsoprovided with a detent 77, which cooperates with a sector 7 9 to hold saidy lever `Alocked'. When the sleeve 42 is pushed'lon- "'gitudinally into the pulley 60, the sleeve 42aiswi`thdrawn from the pulley 61, so that wh'enthe former is expanded the latter is contracted,vand vice versa.- When the sleeve A ,42, for example, is pushed inward the cover- 40plate 32'is`given a partial rotation counterclockwise', and the teeth 84. are moved outward in'tlieslots 36 thus moving the balls 28itoward the right y(as viewed in Fig. 5) .an'dthefprojections 22 on the vanes upward 425i to increase the diameter ofthe pulley. It

willi be noted' that the pitch of the splines 46and 48 is'verygradual, so that there is noi tendency ofthe belt to cause the pulley to contractybyrotating the heads or flanges oiof the pulley on the sleeve 42, and the detent," 7 7 holds the adjusting,y leverlocked.

What I claim is Y 1`.v VAn expansible pulley, comprisingk a pair? of disks having slots, a plurality of "ballcarriers mounted on said disks and each provided with an endless series of balls, a plurality ofmovable sections guided in said slots and engaging said balls, and a memberV rotatable relatively to said plate andhaving means` forv engaging said balls,V whereby Y upon the relative rotation of said members saidsection's Vare moved;

22'In`an expansible pulley: the;combinav I tion" of '-a shaft ;.apulley frame mounted 5` thereon; applu'rality of rim sections mounted The sleeve 42`extends across in said lframe and movable therein to vary their radial distance from said shaft; a plurality of endless ball races corresponding to said rim sections and mounted inv said frame; a plurality of endless series of balls confined in said races and operatively engaging corresponding rim sectionsI to move the latter when said ball series are moved; and means for simultaneously moving the series of balls in said races to move said rim sections simultaneously.

3. In an expansible pulley, the' combination of a shaft; a pulley frame mountedl thereon; a plurality of rim sections lmounted in said frame and movable therein to vary their radial distance from said shaft; a plu rality of endless ball races corresponding to said rimv sections, mounted in said frame; a plurality of endlessseries'of balls ino'v-r able -in said races andV in operativeeng'a'gementl withsaid vrim sections to move the' same when said series 'of balls are moved;

an actuator rotatably mounted with referi" ence'to said frame and shaft, and opera#VV tively engaging said seriesof ballsito'mtove the same simultaneously when said actuator is so rotated; and meansV for rotating actuator relatively to said'y fra'rneland'- shaft'.

v4. In anI exp'ansible pulley, the combination of a shaft; a pulley frame mounted' thereon; a' plurality of rim sections "mounted in said frame and movable thereintovary their radial' distance from the shaft; a'fpli'- said rim'sections dmounted in saidframe;

said series ofballs tomove the Vsame simultaneously when the said actuator is so ro tated; and a sleeve axially movable on said shaft and loperatively connected with said actuator torotate the same relatively to said frame and shaft when said'sleeve is so moved. l y

5.- In" an expansible pulley the combina-- thereon and provided with-substantially ra- Y dial slots; a plurality of movable rim sec# tions mounted inc said frame andv having portions extendinglint-o and guidedl by said slots; a plurality ofl endless ball races one for each of said slots and each having a radial Aportion parallel to its corresponding slot; a plurality of'` endlessseries cof-balls@ guided by saidraces and operatively engage ingthe portions of the rim sections extending into the aforesaid' slots `to'move said rimA sections whenV said ball series are moved;v` and an actuator for moving! allf Said ball?-V series n in=v unison.

6l' The combinationof'a shaft; ia pulley,"

tionv of a`shaft; a pulley frame mounted V lao frame mounted thereon and provided With radial slots; a plurality of movable rim sections mounted in said frame and having portions projecting into said slots; a plurality of endless ball races one for each of said slots, and each having a radial portion adjacent its corresponding slot; a plurality of endless series of balls guided by said races, each series operatively engaging a portion of a rim section guided by the corresponding slot to move said rim section when said ball series is moved; and an actuating device rotatably mounted With reference to said frame and shaft and engaging said ball series to move the same in unison When said actuator is so rotated.

7. The combination of a shaft; a pulley frame mounted thereon and provided with radial slots; a plurality of movable rim sections mounted in said frame and having portions projecting into said slots; a plurality of endless ball races one for each of said slots, and each having a radial portion adjacent its corresponding slot; a plurality of endless series of balls guided by said races each series operatively engaging a portion of a rim section guided by the corresponding slot to move said rim section when said ball series is moved; an actuator rotatably mounted with reference to said frame and shaft and engaging said ball series to move the same in unison When said actuator is so rotated; and a sleeve axially movable With reference to said shaft and operatively connected to said actuator to rotate the same by the axial movement of said sleeve.

In testimony whereof I have affixed my signature in the presence of two Witnesses.

MELVIN L. SEVERY. Witnesses:

EDWARD S. CROCKETT, WILLIAM J. SPERL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0. 

